DUGWAY PROVING GROUND, Utah — A space capsule holding what scientists hoped would be clues to the origin of the solar system fell to a crash landing on Earth Wednesday after its parachute failed to open.

A pair of helicopters, helmed by stunt pilots, had been ready to snatch the refrigerator-sized parachute with a hook as the Genesis capsule descended. But there was no sign that the parachute opened, and video from the scene showed the 452-pound (205-kilogram) capsule hurtling toward the ground at the military Utah Test and Training Range. The capsule broke open on impact.

The $260 million Genesis mission was bringing back to Earth a set of fragile disks containing billions of atoms collected from solar wind, the first cosmic samples to be returned to Earth from beyond the moon.

Now, the fate of those atoms is uncertain. NASA officials believed the disks would shatter even if the capsule hit the ground with a parachute.

“There was a big pit in my stomach,” said physicist Roger Wiens of Los Alamos National Laboratory, which designed the atom collector plates. “This just wasn’t supposed to happen. We’re going to have a lot of work picking up the pieces.”

Studying solar system's origins
Together, the charged atoms captured over 884 days on the capsule’s disks of gold, sapphire, diamond and silicone are no bigger than a few grains of salt — but if the samples survived, that could be still be enough to help reconstruct the chemical origin of the sun and its family of planets, scientists said. They had hoped to study the material for at least five more years.

Video: Genesis probe crash
Wiens was confident they could retrieve the pieces, but said “it’s going to be a lot tougher to sort out the pieces of broken material.”

The five disks were of different thicknesses, Wiens said, which could make it easier for scientists to sort out shattered remnants and put pieces back together like a puzzle.

It was not immediately clear how soon the retrieval process could be completed. NASA engineers said the parachute system failed because the explosives meant to open the parachute never fired — perhaps because of a faulty component aboard the spacecraft.

Those explosives might still be active, said Chris Jones, solar system exploration director for NASA’s Jet Propulsion Laboratory. “That presents a safety hazard to recovery crews,” he said.

NASA would convene a review board to determine exactly why the system failed, said Andrew Dantzler, who oversees the agency's Discovery space science program.

Choreographed return to Earth
The Genesis probe was launched in 2001 and traveled in tandem with Earth, just outside the planet's magnetic shield, for three orbits of the sun. It started the return trip months ago, following a tightly choreographed scenario. As Earth's gravitational pull brought it closer, the capsule picked up speed rapidly, reaching velocities of 25,000 mph or 11 kilometers per second. The capsule's descent was then slowed by atmospheric re-entry.

That’s when the parachute and the helicopters were supposed to take over.

Both Cliff Fleming, the lead helicopter pilot, and backup pilot Dan Rudert had years of experience as Hollywood stunt pilots, and they replicated the retrieval in dozens of practice runs. But because the parachute never opened, they never had a chance to snag the capsule. Instead, the probe slammed into the Utah desert at an estimated speed of 193 mph (309 kilometers per hour), Jones said.

NASA was still debating what to do with the broken capsule. The original scenario called for the probe to be packed up and driven with a convoy of armed guards to Houston’s Johnson Space Center in a truck. Genesis project manager Don Sweetnam said that plan was still in effect.

"All the materials that can be recovered will make their way to Johnson Space Center for curation," he said. However, the impact and resulting contamination most likely has degraded the quality of the samples, scientists said.

Surviving samples of the solar particles would be parceled out for analysis to the University of California at Los Angeles and the University of Chicago’s Argonne National Lab.

Looking back, looking ahead
The crash represented a public-relations setback for the space agency, which weathered the twin failures of Mars missions in 1999 and is still dealing with the aftermath of last year's loss of the shuttle Columbia and its crew. On the positive side of the ledger, NASA has scored triumphs in the past year with its twin Mars rover missions and the Cassini mission to Saturn.

Another NASA probe named Stardust is due to return to the Utah Test and Training Range in 2006, bearing samples of cosmic dust from a comet's wake. Stardust uses a similar parachute system to brake its descent. However, the Stardust capsule is designed to be cut loose from its parachute and survive impact.

NASA also is considering plans to bring samples back from Mars sometime in the next decade.

This report includes information from The Associated Press and MSNBC's Alan Boyle.